各位同學前輩，我這個代碼運行顯示正確，但是顯示的都是亂碼是怎么回事？

#include

int main()

{ ? ?char c = 97;?

? int n = c ? ? ? ?//將c賦值給n ?

?float f = c ? ? ? //將c賦值給f

?? double d = c ? ? //將c賦值給d

?? printf("%d\n",n); ??

printf("%f\n",f); ??

printf("%lf\n",d);

?? return 0; ??

}?

顯示結果：?

/249/5117/8r7b/hello.c: In function 'main':
/249/5117/8r7b/hello.c:6:5: error: expected ',' or ';' before 'float'
? ? float f = c ? ? ? //將c賦值給f
? ? ^
/249/5117/8r7b/hello.c:9:19: error: 'f' undeclared (first use in this function)
? ? printf("%f\n",f);
? ? ? ? ? ? ? ? ? ^
/249/5117/8r7b/hello.c:9:19: note: each undeclared identifier is reported only once for each function it appears in
/249/5117/8r7b/hello.c:10:20: error: 'd' undeclared (first use in this function)
? ? printf("%lf\n",d);